An aircraft comprises an electrical and electronic bay (known as an E & E bay) in which are installed various items of equipment, required, notably, for the piloting of the aircraft and for the control of the electrical energy and of other networks such as the communications and fluid networks. Thus this bay generally comprises a plurality of electronics cabinets in which are arranged various electrical and electronic elements, grouped in electrical and electronic systems. In the remainder of the description, the abbreviation E & E signifies “electrical and/or electronic”.
As shown in FIG. 1, an electronics cabinet comprises a frame 12 and at least one E & E system 10 integrated into said frame 12.
In one embodiment, the frame 12 of a cabinet has a substantially parallelepipedal shape with solid lower and upper faces and perforated right and left faces, made of mesh material.
In one embodiment, an E & E system 10 has a substantially parallelepipedal shape with a front face 14, a rear face 16 and four side faces (lower, upper, right and left).
An E & E system 10 also comprises connection means 18 for its electrical and electronic connection, and, if necessary, controls and/or indicators 20 arranged on the front face 14.
In one embodiment, a frame 12 comprises at least one shelf 22 on which at least one E & E system 10 rests, and a back 24.
Preferably, the E & E system 10 is of the type known as rackable, a sliding joint 26 being interposed between said E & E system 10 and the frame 12. Thus the E & E system 10 is placed in position by a translational movement of said E & E system 10 with respect to the frame 12 in a direction defined by the sliding joint 26.
Advantageously, the connection means 18 are interposed between the rear face 16 of the E & E system 10 and the back 24 of the frame 12, as shown in FIG. 2.
According to a first constraint, the E & E systems 10 generate a certain amount of heat which must be removed to allow them to operate in an optimal manner. Generally, use is made of a flow of cooling air which passes across the E & E systems to remove the amount of heat produced by them. Additionally, in order to promote the circulation of the air flow provided for cooling, the right, upper and left side walls of the E & E system 10 are spaced apart from the walls of the frame 12, and the right and left faces of the frame 12 are perforated.
According to a second constraint, an E & E bay of an aircraft is not a compartment of the clean room type in which the particle concentration is controlled. The atmosphere of the E & E bay therefore includes numerous fine particles which may be put into suspension (notably as a result of the air flows generated to cool the E & E systems 10) and may be deposited on some areas of the E & E systems.
The use of carbon for the aircraft structure gives rise to the formation of fine carbon particles, which are electrically conductive and which may harm the operation of the E & E systems, especially since these E & E systems are increasingly complex and sensitive to fine particles of carbon or other materials.
To limit the risks of malfunction, a first solution is to use dust-tight connection means 18 and E & E systems adapted to operate in dusty environments, for example varnished electronic circuit cards.
This solution tends to increase the cost of the aircraft, because of the high cost of dust-tight connection means 18 and E & E systems adapted to operate in dusty environments.
Another solution is to integrate the E & E systems 10 into an electronics cabinet fitted with a door, as shown for example in DE-101.19.095.
This solution is unsatisfactory for the following reasons:
A first drawback is that the presence of a door tends to increase the weight on board the aircraft.
Another drawback is that a free area must be provided in front of the electronics cabinet so that the door can be opened by pivoting. However, aircraft designers tend to reduce the spacing between the cabinets in order to reduce the volume of the E & E compartment.
Another drawback is that the door limits access to the front faces 14 of the E & E systems. In order to access the controls on the front face, therefore, the door must be opened, inevitably resulting in the ingress of fine particles.
This problem may also arise in a computer in which an electronic circuit card is removably fitted, or more generally in any electronics structure such as an electronics cabinet, a computer or any other sub-assembly comprising at least a frame in which at least one E & E system such as a computer or an electronic circuit card is fitted.